Some electrical plugs are provided in electrical plug-in connectors in order to produce a releasable electrical connection between a first electrical line and a second electrical line, or between an electrical line and an electrical device. The electrical plugs may be used in a variety of fields of application, among others, within the industry of vehicle electronics, for example, for use as connector plugs for cigarette lighters. Due to the extreme environmental conditions in this field, high standards must be met with regard to the plug's vibratory strength, resistance to corrosion and temperature, and current-carrying capacity. Furthermore, the connection provided by such a plug must be able to be disconnected and reliably connected again as easily as possible.
A plug is disclosed in U.S. Pat. No. 6,364,686 that comprises a longitudinally divided spring arm with two spring arm portions 14, 15. The spring arm portion 14 has a latching projection 16 that is provided for engagingly connecting to the corresponding opening 20 in the socket 2. The spring arm portion 15 comprises a projection 17 that is provided in order to tightly engage with a correspondingly formed recess 21 in the socket 2. While the object of the latching projection 16 is to ensure a reliable connection between the plug 1 and the socket 2 by means of latching engagement, the object of the projection 17 is to provide a connection between the plug 1 and the socket 2 so that the plug 1 and the socket 2 are not loose relative to each other.
The spring arm portion 14 is further provided with a releasing button 18 by which means the two spring arm portions 14, 15 can be simultaneously actuated in such a way that the plug 1 is released from the socket 2.
However, as plugs of this type are used, above all, in the automotive industry, the plugs pose the danger that, when assembled, they may not properly lock into the socket by means of their latching projection or latch due to the application of force at the spring arm during insertion of the plug into the socket. In other words, while force is necessary for inserting or introducing the plug into the corresponding socket, it is possible that the person assembling the plug may, during assembly, prevent the spring arm from moving and thus block it with one of their fingers, for example a thumb, possibly preventing the plug from properly locking into the socket. If the plug does not properly lock into the socket, the plug can later become disengaged while in use. This is of particular concern with regard to plugs having sealed plug-in connectors since excess pressure may develop that can force an inadequately secured plug out of the socket. This results in undesired failure during operation that is also, to some extent, associated with considerable drawbacks.